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Source Naturals® 5-HTP 100 mg (120 Capsules)
Clinical Editorial Note: Reviewed by VitaNet® Nutritional Sciences Team & Certified Nutrition Specialist (CNS) Last medically reviewed: August 2026 | Compliant with DSHEA GuidelinesWhat Is 5-HTP & How Does It Work?
5-Hydroxytryptophan (5-HTP) is a naturally occurring intermediate metabolite between the essential amino acid L-tryptophan and the neurotransmitter serotonin (5-hydroxytryptamine). Derived from the seeds of the African shrub Griffonia simplicifolia, this botanical extract delivers targeted neurochemical support for emotional well-being, stress resilience, and restorative sleep cycles.The Pharmacokinetics of 5-HTP vs. L-Tryptophan
Unlike dietary L-tryptophan, supplemental 5-HTP bypasses the body's rate-limiting enzymatic step—tryptophan hydroxylase (TPH). This physiological pathway offers distinct advantages:- Direct Serotonin Synthesis: 5-HTP is converted directly into serotonin via the enzyme aromatic L-amino acid decarboxylase (AAAD), requiring significantly less metabolic energy.
- Direct Blood-Brain Barrier Transport: While dietary L-tryptophan must compete with other large neutral amino acids (such as leucine, isoleucine, and valine) for transport across the blood-brain barrier, 5-HTP crosses readily without carrier competition.
- Melatonin Pathway Precursor: In the pineal gland, serotonin is further synthesized into melatonin, the neurohormone responsible for synchronizing circadian rhythms and signaling sleep onset.
Primary Health Applications
- Positive Mood & Emotional Balance: By supporting steady cerebral serotonin levels, 5-HTP helps maintain emotional balance, mood stability, and resilience during everyday nervous tension.
- Sleep Architecture & Latency: When taken in the evening, 5-HTP encourages melatonin synthesis, helping reduce the time it takes to fall asleep (sleep latency) without disrupting natural REM patterns.
- Satiety & Appetite Regulation: Clinical investigations suggest that central serotonin signaling plays an active role in post-meal satiety, potentially curbing emotional carbohydrate and sugar cravings.
Suggested Usage & Timing Protocols
- For Mood and Daytime Relaxation: Take 1 capsule once or twice daily with meals to minimize potential stomach sensitivity.
- For Sleep Support: Take 1 capsule 30 to 45 minutes before bedtime with a small carbohydrate snack or light beverage to facilitate rapid uptake.
- Cycling Guidance: For sustained results, consider using 5-HTP for cycles of 8 to 12 weeks, followed by a 2- to 4-week wash-out period, unless otherwise directed by a qualified healthcare professional.
Supplement Facts & Formula Transparency
| Supplement Facts | |
| Serving Size: 1 Capsule | Servings Per Container: 120 |
| Active Compound | Amount Per Serving |
| 5-Hydroxytryptophan (from Griffonia simplicifolia seed extract) | 100 mg* |
| *Daily Value (DV) not established. |
- Other Ingredients: Microcrystalline cellulose, gelatin (capsule shell), silica, and magnesium stearate.
- Allergen & Purity Declarations: Contains no yeast, dairy, egg, gluten, corn, soy, or wheat. Formulated without sugar, starch, salt, artificial colors, flavors, or synthetic preservatives.
Safety, Contraindications & Drug Interactions
Because 5-HTP directly influences central serotonin concentrations, adhere strictly to the following safety precautions:1. Serotonin Syndrome Warning (Do Not Combine with Antidepressants)
Do not use this product if you are currently taking prescription medications that increase serotonin. Combining 5-HTP with these drugs may lead to Serotonin Syndrome, a serious condition characterized by agitation, rapid heart rate, muscle rigidity, and hyperthermia. Contraindicated medications include:- SSRIs (e.g., Fluoxetine, Sertraline, Citalopram, Escitalopram)
- SNRIs (e.g., Venlafaxine, Duloxetine)
- MAOIs (e.g., Phenelzine, Tranylcypromine)
- Tricyclic Antidepressants (e.g., Amitriptyline)
- Other supplements affecting serotonin pathways, including St. John’s Wort (Hypericum perforatum) and SAM-e.
2. Pregnancy & Nursing
Not intended for use by pregnant, lactating, or nursing women due to insufficient clinical safety data in neonatal development.3. Surgical Clearance
Discontinue supplementation at least two weeks prior to elective surgical procedures, as certain general anesthetics and postoperative analgesics interact with serotonergic pathways.4. Mild Gastrointestinal Effects
Mild, transient nausea or abdominal cramping can occur when initiating 5-HTP. Starting with food or taking a lower dose can resolve gastrointestinal sensitivity.Clinical References & Literature
- Birdsall, T. C. (1998). 5-Hydroxytryptophan: a clinically-effective serotonin precursor. Alternative Medicine Review, 3(4), 271-280.
- Turner, E. H., et al. (2006). Serotonin a la carte: supplementation with the serotonin precursor 5-hydroxytryptophan. Pharmacology & Therapeutics, 109(3), 325-338.
- Cangiano, C., et al. (1998). Effects of oral 5-hydroxy-tryptophan on energy intake and macronutrient selection in non-insulin dependent diabetic patients. International Journal of Obesity, 22(7), 648-654.
Frequently Asked Questions
What makes 5-HTP more direct than dietary L-tryptophan?
5-HTP is one metabolic step closer to serotonin than L-tryptophan. Dietary L-tryptophan must first be converted into 5-HTP by the rate-limiting enzyme tryptophan hydroxylase (TPH) and must compete with other amino acids to cross the blood-brain barrier. Supplemental 5-HTP bypasses this bottleneck and readily crosses into the central nervous system without transport competition.Should I take 5-HTP in the morning or at night?
Your ideal timing depends on your health objective:- For daytime mood support and stress balance: Take 1 capsule once or twice daily with a meal to support sustained serotonin production.
- For sleep onset and latency: Take 1 capsule 30 to 45 minutes before bedtime. Pairing it with a light carbohydrate snack can facilitate quicker cerebral uptake.
Can I take 5-HTP if I am already taking an antidepressant?
No. Do not take 5-HTP alongside prescription antidepressants, including SSRIs (e.g., sertraline, fluoxetine), SNRIs (e.g., duloxetine, venlafaxine), MAOIs, or tricyclics. Combining 5-HTP with medications or herbs that elevate serotonin (such as St. John’s Wort) creates a dangerous risk of Serotonin Syndrome, a potentially life-threatening medical emergency. Consult your prescribing physician before introducing any serotonergic compound.How quickly does 5-HTP begin working?
For sleep latency, many individuals notice improved rest within the first few nights of use as 5-HTP converts to melatonin. For general mood regulation, emotional balance, and satiety support, noticeable effects typically develop after 1 to 3 weeks of consistent daily administration.Is it safe to take 5-HTP continuously without taking breaks?
Clinical practitioners generally recommend cycling 5-HTP rather than taking it indefinitely. A typical protocol involves 8 to 12 weeks of consistent supplementation followed by a 2- to 4-week washout period. This reset helps preserve natural receptor sensitivity and enzymatic activity.Is Source Naturals 5-HTP vegetarian or vegan-friendly?
No. While the active 5-HTP compound is derived from the botanical seed extract Griffonia simplicifolia, the capsule shell contains bovine/porcine gelatin. However, the formulation is entirely free from common allergens, including gluten, wheat, soy, corn, dairy, egg, and yeast.What should I do if 5-HTP causes mild nausea or an upset stomach?
Because serotonin receptors are abundant in the gastrointestinal tract, initial doses can occasionally cause transient nausea or cramping. Taking your capsule with a substantial meal rather than on an empty stomach generally alleviates this discomfort. If symptoms persist, discontinue use and consult a healthcare provider.
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