L-Tryptophan is out of stock
Back Soon

Source Naturals L-Tryptophan

120 capsules | $0.22/Capsule


(11% Off)
FREE shipping unlocked

Why You’ll Love It

The essential amino acid L-tryptophan is the precursor for the synthesis of melatonin and serotonin, a hormone and a neurotransmitter involved with mood and stress response. It helps support relaxation, restful sleep, and a positive outlook. This tryptophan tablet includes vitamin B-6, which is required to convert tryptophan to serotonin. If needed, L-tryptophan is converted to niacin in the body, an important B vitamin. Source Naturals L-Tryptophan is extremely pure and is regularly tested to ensure the highest standards of quality.

SKU: 021078019855

About This Brand

Source Naturals

“Take responsibility for your health.” That’s the mantra Source Naturals has championed since the early 1980s, and the company’s line of more than 600 supplements and wellness products help people do just that. Even today, federal government regulations around supplement products are still lax, and don’t require detailed labeling. So it’s important to double-check what’s really going inside each...
Shop the brand


Other Ingredients: microcrystalline cellulose, stearic acid, modified cellulose gum, and silica

Disclaimer: Information, statements, and reviews regarding products have not been evaluated by the Food and Drug Administration. Results vary person to person, and there is no guarantee of specific results. Thrive Market assumes no liability for inaccuracies or misstatements about products.

Nutrition information

Serving Size:
1 tablet
Servings Per
Amount per serving
% daily value
Vitamin B-6 (as pyridoxine HCl)
20 mg
Iron (naturally occurring)
390 mcg
1 g
† Daily Value Not Established

Warning: If you are pregnant, may become pregnant, breastfeeding, or are taking medications such as SSRIs or MAOIs, consult your health care professional before using this product. This product may cause drowsiness. Do not use if either tamper-evident seal is broken or missing. Keep out of the reach of children. Store in a cool, dry place. 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.

16 Members have left reviews!

Fabulous solution for hyperactive dog

Posted   by Andrea from BIG BEAR LAKE, California
Verified Purchase
All studies say that l-tryptophan does NOT work in hyperactive or aggressive dogs. I’ve been rescuing hunting dogs for 22years and my latest rescue is an ADD dog that couldn’t even fall asleep at night (too much trauma and too many chemical drugs given) This stuff works wonders. He’s a normal puppy after just two pills. Chills out after his walks, doesn’t yap anymore, falls asleep at 7pm and sleeps through the night. I did a lot of research and the natural stuff works better than the chemicals. Hooked and buying again so puppy can sleep and so can the rest of the family .... if you use it for your dog research the dosage carefully ;-)
Helpful review?

Love this brand

Posted   by Mary from SANTA ROSA, California
Verified Purchase
I use this at night to help sleep. I like this brand above all.
Helpful review?


Posted   by Hawk from OJAI, California
Verified Purchase
helpful for sleep. i take 1 capsule, not the high dose recommended on the label. not sure about the gelatin capsule though.
Helpful review?

Seems to work really well

Posted   by Lorraine from Clifton Park, New York
Verified Purchase
My husband takes this along with other sleep aids - but this is the one that really seemed to make it all work together.
Helpful review?

Quality Brand

Posted   by Sarah from South Lake Tahoe, California
Verified Purchase
Good price for a quality product
Helpful review?


Posted   by Monica from GLEN GARDNER, New Jersey
Verified Purchase
Helpful review?

Didn’t notice any effect

Posted   by Cindy from SAN ANGELO, Texas
Verified Purchase
Don’t know if it worked.
Helpful review?

Sleep help

Posted   by Kyle from HILLSBOROUGH, New Jersey
Verified Purchase
Helps on nights when I can't seem to fall asleep. Sometimes I use this tryptophan and sometimes I use the Source Naturals GABA Calm. I like them both.
Helpful review?

This truly helps me sleep

Posted   by Jennifer from BROOKLYN, New York
Verified Purchase
I absolutely love this! I live in NYC, so sleeping through the night is sometimes a challenge. This gives me a deep sleep and helps me fall asleep faster.
Helpful review?

good price

Posted   by CHRISTINA from Santa Cruz, California
Verified Purchase
My doctor recommended taking this before bed for improved sleep. I was buying it at a pharmacy and it cost $10 more a bottle. I was glad to find this on thrive.
Helpful review?
(Displaying 10 of 16 reviews)