NATROL
NATROL: B-Complex Fast Dissolve Coconut Flavor, 90 Tablets ('047469063313)
Promotes Energy! Enjoy It Any Time You Need A Boost!
Natrol’s B-Complex Fast Dissolve offers the benefits of Biotin and other B-complex vitamins. These water-soluble vitamins are the vital co-factors in carbohydrate, fat and protein metabolism, generating energy. Additionally, Biotin is involved in the process that ensures proper functioning of the sweat glands, nerve tissue and bone marrow.
Numerous clinical studies have shown that these vitamins are essential for the optimal functioning of the cardiovascular, nervous and immune systems. In addition, Biotin has a long history of use for healthy, luxurious hair, radiant skin, and strong nails
Natrol’s B-Complex Fast Dissolve also offers the benefits of Coconut Extract, derived from coconut water, a liquid rich in electrolytes and B-vitamins, found inside the shell of the coconut. Coconut water has been traditionally used to re-hydrate after exercise.
NATROL: B-Complex Fast Dissolve Coconut Flavor, 90 Tablets
NATROL: Garcinia Cambogia Extract Appetite Intercept, 120 Capsules ('047469067342)
The natural way to weight loss!
Hunger and cravings can leave you feeling powerless to control your weight. Fight the hunger and break the cycle with patented Super CitriMax® Garcinia Cambogia.
Super CitriMax® is derived from the dried fruit of Garcinia Cambogia, a native fruit of Asia and Africa. Natrol® Super CitriMax® Garcinia Cambogia Extract is a natural non-stimulant dietary supplement that is made from extracts of the Garcinia Cambogia fruit. The fruit, Garcinia Cambogia, contains the key ingredient Hydroxycitric Acid (HCA), which is extracted from the rind and dried fruit.
Natrol&® Super CitriMax® Garcinia Cambogia Extract and its key ingredient Hydroxycitric Acid (HCA) helps control your appetite, support weight-loss, and maintain a healthy weight. Scientist believe that the HCA in Garcinia Cambogia extract helps inhibits the production of fat in the body, may increase serotonin levels, and suppresses appetite. HCA is essential for increasing metabolism and burning fat
Natrol® Super CitriMax® Garcinia Cambogia Extract is made with Super CitriMax® Garcinia Extract. Super CitriMax® Garcinia Extract has a high concentration of the active ingredient Hydroxycitric Acid (HCA) and is lab verified for potency and guaranteed quality. Natrol®Super CitriMax® Garcinia Cambogia Extract contains a 60% concentration of hydroxycitric acid (HCA).
NATROL: Garcinia Cambogia Extract Appetite Intercept, 120 Capsules
NATROL: DHEA 50 mg, 60 Tablets ('047469161064)
What is DHEA?
DHEA (dehydroepiandrosterone) is a hormone that is secreted by the adrenal gland in the human body. DHEA serves as a precursor to male and female sex hormones.
NATROL: DHEA 50 mg, 60 Tablets
NATROL: Cranberry Fast Dissolve 250 mg, 120 Tablets ('047469063306)
Natrol® Cranberry Fast Dissolve features CranMax®! All the benefits of Cranberries in a form that will dissolve completely on your tongue and be swallowed with liquids!
CranMax® is a cranberry (Vaccinium Macrocarpon) based active ingredient which is clinically proven to help reduce the occurrence of bladder infection or urinary tract infections (UTIs) among women experiencing recurrent UTIs. Urinary tract infections (UTIs) are considered to affect at least one woman in five, with most affected woman having recurrent cases.
CranMax® is made from 100% cranberry fruit solids. CranMax® is first to possess the benefits of Bio-Shield® technology. The concentrated cranberry actives are infused into the Bio-Shield carrier which helps carry the product through the stomach acids without deterioration, and to the lower GI tract where they are released and absorbed by the body over an 12-16 hour period of time.
CranMax® is manufactured through a proprietary process that intensifies the natural benefits of the whole cranberry, without the use of any solvents, preservatives, sugars, water, flavorings or color.
Many have relied on Natrol® Cranberry Fast Dissolve for the health of their urinary tract and immune system!
NATROL: Cranberry Fast Dissolve 250 mg, 120 Tablets
NATROL: Cognium, 60 tb ('047469072308)
A breakthrough in brain health, Natrol Cognium is powered by a unique ingredient backed by human clinical studies that show statistically significant improvements in memory and cognition in as little as four weeks.
NATROL: Cognium, 60 tb
NATROL: Cognium Extra Strength, 60 tb ('047469073404)
Extra Strength Cognium is powered by a silk protein hydrolysate that is the #1 most clinically studied ingredient for memory among leading brain health supplements. Multiple human clinical studies show statistically significant improvements in memory and concentration. Additionally, Extra Strength Cognium enhances mental agility by improving focus, learning and attention. † Natrol Extra Strength Cognium keeps your mind sharp and your memory strong† #1 fastest growing brain health brand #1 most studied ingredient for memory among leading brain health brands Clinically proven to improve memory and concentration† Enhances mental agility by improving focus, learning and attention† Safe, natural and stimulant free Results in as little as 4 weeks Support your brain with Extra Strength Cognium, the smart choice in brain health.
NATROL: Cognium Extra Strength, 60 tb
NATROL: Cinnamon Extract 1000 mg, 80 Tablets ('047469044589)
Cinnamon has been treasured for its exquisite flavor and aroma as well as its healing properties at least since the time of ancient Greece. Now, Natrol has brought to market a concentrated form of this sweet spice - Natrol Cinnamon Extract, and important ingredient in the recipe for your health.
NATROL: Cinnamon Extract 1000 mg, 80 Tablets
NATROL: Cinnamon Biotin Chromium, 60 tablets ('047469048983)
Triple Action Support for Sugar Metabolism!
Cinnamon: Provides Natural Antioxidant Protection
Chromax® (Chromium Picolinate): In Conjunction with Insulin, Supports Metabolism†
Biotin: For the Metabolism of Protein and Fat
Natrol® Cinnamon Biotin Chromium provides a powerful, triple action formula of Cinnamon, Biotin & Chromax® (Chromium Picolinate) to support sugar, protein and fat metabolism and help maintain healthy blood sugar levels already within the normal range.
NATROL: Cinnamon Biotin Chromium, 60 tablets
NATROL: Biotin Strawberry Flavor 5000 mcg, 90 Tablets ('047469063238)
The Natrol Biotin you trust in Fast Dissolving form! Our Biotin is the preferred choice when it comes to restoring your naturally lustrous hair and resilient nails while keeping your diet and shape on track!
Clinical studies have shown that those deficient in biotin experience hair loss, brittle nails and unhealthy skin. Biotin plays a key-role in the body and is the important nutrient for the growth and maintenance of your hair, nails and glowing skin.
Biotin is a B vitamin, also known as vitamin H or Vitamin B7. Biotin is also essential for your metabolic processes including the metabolism of fats and amino acids, production of fatty acids, and cell growth. This vitamin processes nearly every type of food that you ingest, including carbohydrates, proteins and fats. When biotin levels are at the proper levels in your body, the food that you take in will be processed quickly.
Natrol® Biotin supplement supports the health of the skin, thick shiny hair and strong nails as well as of the nerves and digestive tract.
NATROL: Biotin Strawberry Flavor 5000 mcg, 90 Tablets
NATROL: Biotin Plus + Lutein, 60 tb ('047469071417)
Fortified with biotin and lutein, Natrol® Biotin Plus hydrates your skin with clinical strength lutein and promotes healthy hair and nails with biotin.
NATROL: Biotin Plus + Lutein, 60 tb
NATROL: Biotin Maximum Strength 10,000 mcg, 100 Tablets ('047469053963)
What is Biotin? Biotin, also known as vitamin H, is a B vitamin that plays a key-role in the body. Biotin assists in various metabolic reactions in the body, including the metabolism of fats and amino acids, production of fatty acids, and cell growth. Biotin supports the health of the skin, hair and nails as well as of the nerves and digestive tract.
NATROL: Biotin Maximum Strength 10,000 mcg, 100 Tablets
NATROL: Guarana 200 mg, 90 Capsules ('047469008000)
End the fatigue and curb your hunger!† Try Natrol® Guarana (an exotic fruit from the Amazon)!
Natrol® Guarana is a concentrated extract from the seeds of the Guarana climbing plant. Guarana is popularly used for weight loss, to enhance athletic performance, as a stimulant, and to reduce mental and physical fatigue. Guarana works by stimulating the central nervous system, heart, and muscles. Guarana is also cleanses the blood and prevents clotting.†
Natrol® Guarana offers mental support while suppressing your appetite and boosting your energy level – all in an easy-to-swallow capsule!†
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
NATROL: Guarana 200 mg, 90 Capsules
NATROL: Alpha Lipoic Acid 600 mg, 45 tb ('047469052294)
Natrol® ALA is also an antioxidant, a substance that neutralizes potentially harmful chemicals called free radicals and thereby helps prevent cell damage in the body. What makes alpha lipoic acid unique is that it functions in both water and fat unlike the more common antioxidants such as vitamins C and E, and it is able to re-cycle antioxidants such as vitamin C and vitamin E after they have been used up. Numerous clinical and experimental data also show evidence that alpha-lipoic acid can improve the function and conduction of neurons in diabetes, as well as help with memory loss and mental acuity.
Whole Body Cell Rejuvenation
Helps protect Against Age-Related Damage
NATROL: Alpha Lipoic Acid 600 mg, 45 tb
NATROL: Alpha Lipoic Acid 600 mg, 30 Capsules ('047469044725)
Alpha Lipoic Acid (ALA) is a vitamin-like compound that is used in the body to break down carbohydrates and generate energy for the body’s organs.
Natrol® ALA is also an antioxidant, a substance that neutralizes potentially harmful chemicals called free radicals and thereby helps prevent cell damage in the body. What makes alpha lipoic acid unique is that it functions in both water and fat unlike the more common antioxidants such as vitamins C and E, and it is able to re-cycle antioxidants such as vitamin C and vitamin E after they have been used up.
Numerous clinical and experimental data also show evidence that alpha-lipoic acid can improve the function and conduction of neurons in diabetes, as well as help with memory loss and mental acuity.
NATROL: Alpha Lipoic Acid 600 mg, 30 Capsules
NATROL: Alpha Lipoic Acid 300 mg, 50 Capsules ('047469003128)
Alpha Lipoic Acid (ALA) is a vitamin-like compound that is used in the body to break down carbohydrates and generate energy for the body’s organs.
Natrol® ALA is also an antioxidant, a substance that neutralizes potentially harmful chemicals called free radicals and thereby helps prevent cell damage in the body. What makes alpha lipoic acid unique is that it functions in both water and fat unlike the more common antioxidants such as vitamins C and E, and it is able to re-cycle antioxidants such as vitamin C and vitamin E after they have been used up.†
Numerous clinical and experimental data also show evidence that alpha-lipoic acid can improve the function and conduction of neurons in diabetes, as well as help with memory loss and mental acuity.†
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
NATROL: Alpha Lipoic Acid 300 mg, 50 Capsules
NATROL: Advanced Sleep Melatonin 10 mg, 60 Tablets ('047469059644)
Natrol®, the leader in melatonin, is now offering the maximum strength 10mg dosage!
Melatonin, a hormone made by the pineal gland of the brain, helps regulate your sleep and wake cycles.
Natrol® Advanced Sleep Melatonin is a nighttime sleep aid that assists with occasional sleeplessness, while also working to help reduce overall anxiety. It helps to establish normal sleep patterns to give you a more restful, relaxing sleep and in turn, better overall health by promoting a healthy immune system.
Adequate sleep is essential to overall health and performance, and plays a role in the ability to learn, create memories, solve problems and maintain a healthy mental outlook. By contrast, researchers have found that lack of sleep can result in mood swings and an inability to focus and respond quickly.
Natrol® Advanced Sleep Melatonin is the maximum strength available on the market. The 2-layer controlled release tablet gives you an initial 5mg dosage to help you fall asleep fast, and then releases the remaining 5mg over time to help you sleep through the night.
NATROL: Advanced Sleep Melatonin 10 mg, 60 Tablets
NATROL: Advanced Melatonin Calm Sleep Fast Dissolve Strawberry Flavor, 60 tablets ('047469060466)
Dual-Acting Relaxation & Sleep Support!
Natrol® combines the power of Melatonin and L-Theanine in one powerful formula, to help the body relax at the end of the day and aid in falling asleep. A good night’s sleep can help restore the body, promote a healthy immune system, and may even help to maintain a healthy body weight
This powerful formula contains L-Theanine, a naturally occurring component of green tea with relaxing and calming properties. It may help to relax the body by promoting the brain’s alpha waves, similar to those measured in deep meditation. Melatonin is a nighttime sleep aid to assist with occasional sleeplessness. It helps to establish normal sleep patterns to provide a more restful, relaxing sleep and in turn, better overall health
NATROL: Advanced Melatonin Calm Sleep Fast Dissolve Strawberry Flavor, 60 tablets
NATROL: 5-HTP Wild Berry Flavor 100 mg, 30 tablets ('047469060442)
Try Natrol® 5-HTP Fast Dissolve!
The same Natrol® 5-HTP you trust with enhanced Rapid Dissolve Technology to allow the tablets to dissolve up to 30 times faster.
Today’s stress-filled lifestyles and dietary practices may negatively alter your serotonin metabolism which can cause irritability and even depression. Regular use of Natrol® 5-HTP can help provide a more positive and balanced attitude needed to help you maintain a healthy outlook and keep your diet goals by having greater appetite control.
5-HTP (5-Hydroxytryptophan) is a drug-free and naturally occurring plant-derived amino acid that participates in the body’s synthesis of serotonin. 5-HTP is the direct precursor to serotonin.
Natrol® 5-HTP works in the brain and central nervous system by increasing the production of the chemical serotonin. Serotonin can affect sleep, appetite, diet, temperature, and sexual behavior. Serotonin is the chemical messenger that plays a key role in controlling appetite, insomnia, and enhancing mood
NATROL: 5-HTP Wild Berry Flavor 100 mg, 30 tablets
NATROL: 5-HTP TR Time Release 100 mg, 45 tablets ('047469052287)
Feeling not quite yourself? Keep your mood balanced and appetite under control all day. Natrol’s 5-HTP Time Release slowly and steadily releases 5-HTP over a period of 10 hours.
Today’s stress-filled lifestyles and dietary practices may negatively alter your serotonin metabolism which can cause irritability and even depression. Regular use of Natrol® 5-HTP can help provide a more positive and balanced attitude needed to help you maintain a healthy outlook and keep your diet goals by having greater appetite control.
5-HTP (5-Hydroxytryptophan) is a drug-free and naturally occurring plant-derived amino acid that participates in the body’s synthesis of serotonin. 5-HTP is the direct precursor to serotonin.
Natrol® 5-HTP works in the brain and central nervous system by increasing the production of the chemical serotonin. Serotonin can affect sleep, appetite, diet, temperature, and sexual behavior. Serotonin is the chemical messenger that plays a key role in controlling appetite, insomnia, and enhancing mood.
NATROL: 5-HTP TR Time Release 100 mg, 45 tablets
NATROL: 5-HTP 50 mg, 30 Capsules ('047469008840)
What is 5-HTP?
5-HTP is a naturally occurring plant-derived amino acid that participates in the body’s synthesis of serotonin. Serotonin is the chemical messenger that plays a key role in controlling appetite and enhancing mood. The end result: the positive attitude needed to help you maintain a positive, healthy outlook and keep your diet goals.†
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
NATROL: 5-HTP 50 mg, 30 Capsules
NATROL: 5-HTP 200 mg Time Release, 30 tb ('047469051723)
Natrol® 5-HTP is a 100% drug-free way to promote a calm and relaxed mood by enabling the body’s synthesis of Serotonin, the chemical messenger that greatly helps in enhancing mood. Natrol 5-HTP Time Release slowly releases 5-HTP to help you throughout the day.
NATROL: 5-HTP 200 mg Time Release, 30 tb
NATROL: 5-HTP 100 mg, 30 Capsules ('047469040932)
Natrol® 5-HTP is a naturally occurring plant-derived amino acid that participates in the body’s synthesis of serotonin. Serotonin is the chemical messenger that plays a key role in controlling appetite and enhancing mood. The end result: the positive attitude needed to help you maintain a positive, healthy outlook and keep your diet goals.
NATROL: 5-HTP 100 mg, 30 Capsules
NATROL: Melatonin TR Time Release 5 mg, 100 tablets ('047469048372)
Wouldn’t be nice to fall asleep fast and stay asleep all night long? Look no further! Melatonin TR (Time Release) smartly releases melatonin to your body all night long to keep you sleeping like a baby.
Melatonin, a hormone made by the pineal gland of the brain, helps regulate your sleep and wake cycles.
Natrol® Advanced Sleep Melatonin is a nighttime sleep aid that assists with occasional sleeplessness, while also working to help reduce overall anxiety. It helps to establish normal sleep patterns to give you a more restful, relaxing sleep and in turn, better overall health by promoting a healthy immune system.
Adequate sleep is essential to overall health and performance, and plays a role in the ability to learn, create memories, solve problems and maintain a healthy mental outlook. By contrast, researchers have found that lack of sleep can result in mood swings and an inability to focus and respond quickly.
Natrol Melatonin TR Time Release is also combined with Vitamin B6 to help you have a calm rest so that you wake up refreshed the next morning.
NATROL: Melatonin TR Time Release 5 mg, 100 tablets
NATROL: Water Pill, 60 Tablets ('047469009359)
The answer to water-weight and bloating!
Natrol® Water Pill is an all-natural herbal nutrient blend to help promote a balanced level of fluids in the body when used in conjunction with a healthy diet and exercise program. Natrol® Water Pill also infused enhanced with a high potency Vitamin B-6.
Natrol® Water Pill:
• Helps maintain the body’s natural water balance† • Helps with weight management†
Feel your best naturally with Natrol® Water Pill.†
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
NATROL: Water Pill, 60 Tablets
NATROL: Vitamin D3 10,000 IU, 60 Tablets ('047469060145)
The single most important nutrient recommended for supplementation!
Vitamin D is usually obtained through diet or produced by the skin from the ultraviolet energy of the sun. Poor diet and lack of sun exposure can result in inadequate levels of Vitamin D for optimal health. Additionally, there are very few food sources that contain Vitamin D making it even harder to obtain adequate amounts of Vitamin D needed for superior health.
Researchers now know that vitamin D plays a much larger role in promoting health than simply helping build strong bones. Vitamin D helps regulate healthy cell growth, supports immunity, heart health, breast health, colon and prostate health, normal inflammatory response and healthy aging. Research over the last decade suggests that vitamin D may be the single most important nutrient recommended for supplementation.
NATROL: Vitamin D3 10,000 IU, 60 Tablets
NATROL: Vitamin B-12 Fast Dissolve Strawberry 5000 Mcg, 100 tablets ('047469066727)
High-potency and fast-acting energy and nervous system support!
Feeling tired or low on energy? Vitamin B-12 can help. Vitamin B-12 is a vitamin that is involved in the synthesis of DNA and RNA, form healthy red blood cells, and turn the food we eat into energy to power our metabolism.
Natrol® Vitamin B-12 5000mcg Fast Dissolve delivers high-potency B-12 to boost natural energy levels and support the nervous system. Fast-dissolve is a delivery method that allows vitamin B-12 to quickly dissolve in your mouth and can be swallowed without liquids.
NATROL: Vitamin B-12 Fast Dissolve Strawberry 5000 Mcg, 100 tablets
NATROL: Tonalin CLA, 60 Softgels ('047469008635)
Reduce body fat naturally!†
Tonalin® CLA is derived by a patented process from natural safflower oil.† Experimental research indicates that CLA (Conjugated Linoleic Acid) works with your body’s enzymes involved in fat mobilization and the storage of fat. Human studies indicate that CLA can help reduce body fat mass while maintaining lean muscle.†‡
When Tonalin® CLA is used in conjunction to a balance healthy diet and regular exercise program, it can help maintain healthy body weight.†‡
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
‡ Healthy calorie reduction diet and exercise regimen are essential for weight loss. The amount of weight loss varies by individual and is related to your diet, exercise, daily activities, age and body frame.
NATROL: Tonalin CLA, 60 Softgels
NATROL: Tonalin CLA with Safflower Oil, 90 Softgels ('047469008642)
Reduce body fat naturally!†
Tonalin® CLA is derived by a patented process from natural safflower oil.† Experimental research indicates that CLA (Conjugated Linoleic Acid) works with your body’s enzymes involved in fat mobilization and the storage of fat. Human studies indicate that CLA can help reduce body fat mass while maintaining lean muscle.†‡
When Tonalin® CLA is used in conjunction to a balance healthy diet and regular exercise program, it can help maintain healthy body weight.†‡
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
‡ Healthy calorie reduction diet and exercise regimen are essential for weight loss. The amount of weight loss varies by individual and is related to your diet, exercise, daily activities, age and body frame.
NATROL: Tonalin CLA with Safflower Oil, 90 Softgels
NATROL: Soy Isoflavones, 60 Capsules ('047469009250)
Natural support for women 50+ with Natrol® Soy Isoflavones!†
Natrol® Soy Isoflavones is a women’s natural dietary supplement designed to help provide menopause relief by naturally reducing hot flashes and night sweats. †
Soy Isoflavones help provide relief for women who are experiencing a hormonal change and support bone health. Natrol®Soy Isoflavones is made from non-GMO soy. †
Going through menopausal changes is not easy. Let Natrol® Soy Isoflavones® helps make these changing times easier.
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
NATROL: Soy Isoflavones, 60 Capsules
NATROL: Sleep 'n Restore, 20 Tablets ('047469005023)
Take back your restful sleep with Natrol® Sleep 'N Restore® and wake up refreshed!†
Sleep 'N Restore® helps promote a more restful sleep while supporting your body's natural restoration processes.†
Sleep 'N Restore®'s comprehensive nighttime formula offers the benefits of powerful antioxidants that were shown to scavenge free radicals that could be generated by poor diets and busy lifestyles. With Sleep 'N Restore® you wake up refreshed and ready to tackle the day.†
If you toss and turn at night and feel tired during the day, try Natrol® Sleep 'N Restore®.†
† These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
NATROL: Sleep 'n Restore, 20 Tablets
NATROL: Omega 3-6-9 Complex, 90 sg ('047469009984)
Natrol Omega 3-6-9 Complex provides a potent blend of Omega 3, Omega 6 and Omega 9 complex fatty acids needed for metabolic regulation and structural support.
Omega-3 Fish Oil – Fish oil contains both DHA (Docosahexaenoic Acid) and EPA (Eicosapentaenoic Acid). These Omega-3 fatty acids are key for normal development and growth. Omega-3 fatty acids are very important in preventing and managing cardiovascular and heart health.
Omega-6 Borage Oil – Borage Oil contains essential GLA (Gamma Linolenic Acid). Omega-6 fatty acids play a crucial role in brain functions and muscle development. Omega-6 acts like messengers to trigger immune responses. When used along with other Omega-3 and Omega-9, they help regulate metabolism, maintain bone health, support joint health, and aide in the recovery of the immune system.
Omega-9 Flax Oil – Flax Oil contains a concentrated source of OA Oleic Acid or Omega-9. Omega-9 has been known to help lower LDL (“bad”) cholesterol and raise HDL (“good”) cholesterol. Omega-9 also play a role in controlling blood sugar.
Discover the benefits of Natrol® Omega 3-6-9 Complex – a blend of complex fatty acids that are important for promoting heart health and overall health and well-being.
NATROL: Omega 3-6-9 Complex, 90 sg
NATROL: Omega 3 Fish Oil 1200 mg, 60 softgels ('047469044091)
Give yourself the benefits of "good fats" with Natrol® Omega-3. With 1,200 mg of healthy, purified fish oil, you can provide your body with a healthy balance of the nutrients your body needs to support eye, heart and bone health. A natural source of EPA and DHA, Natrol® Omega-3 can help you achieve optimum health when added to your daily regimen.
NATROL: Omega 3 Fish Oil 1200 mg, 60 softgels