Doctor's Best D-Phenylalanine helps support a healthier mood by slowing down the breakdown of endorphins and enkephalins, and you get dependable, science-backed quality from a brand that stays true to purity.

Available Sizes & Variants:

60 capsules - handy daily dose for ongoing mood support

Benefits & Features:

• Mood support comes from preserving endorphins and enkephalins.
• Star ingredient D-Phenylalanine at 500 mg per capsule slows the enzymes that break down these natural mood and pain-regulating peptides, helping you feel steadier.
• Daily capsules keep dosing simple and slot neatly into any routine.
• Designed for daily use, it supports mood and comfort as part of a balanced wellbeing plan.
• Together, the formula blends with other wellness choices, and might help sustain better emotional resilience when life throws its ups and downs.

Doctor's Best rests on science-forward thinking and clear, transparent ingredient lists, earning trust with straightforward mood and comfort support. This D-Phenylalanine formulation uses vegetarian capsules and simple excipients to keep the focus on the active ingredient. The brand's heritage comes from long-standing expertise in quality control and practical wellness solutions, with other offerings that include herbal supplements and ingredients like n acetylcysteine in different formulas.

D-Phenylalanine 500mg, Modified cellulose (vegetarian capsule), Cellulose, Magnesium stearate (vegetable source).

• GTIN: 753950001107
• Manufacturer: Doctor's Best
• Categories: Best SellersDoctor's BestSubscribe & Save Products
• Best buy: 6 - 24 months+

United Kingdom Shipping:

Orders placed by 2pm (Monday to Friday) are dispatched the same day. Orders placed after 2pm will be dispatched the next working day.

Free shipping on orders over £50 to the UK.

Returns: Our products are meant to make you feel healthy and at your best. If you need to return your item, you can do so free of charge within 30 days in the same original and unopened packaging. Subject to T&C's.

Take 1 or 2 capsules daily, between meals, or as recommended by a nutritionally informed physician. Store in a cool, dry place. Phenylalanine supplements should not be taken by individuals with phenylketonuria (PKU), children, pregnant or lactating women, people with high blood pressure, and anyone taking anti-psychotic medications or MAO inhibitors.

Please consult the product packaging for accurate instructions on how to use the product.

The Active Ingredient Is: D-Phenylalanine

D-Phenylalanine is a non-protein amino acid involved in normal neurotransmitter function related to mood and pain pathways.

This formulation presents D-Phenylalanine in a capsule alongside inert excipients; the ingredient is described as the active component responsible for supporting endorphin and enkephalin activity without referencing additional active formulation components.

What Does D-Phenylalanine Do?

Scientific research suggests that D-Phenylalanine slows the action of enzymes that break down endorphins and enkephalins, helping to maintain higher levels of these endogenous peptides.

In line with EFSA-style function claims, this mechanism plays a role in supporting the normal regulation of mood and comfort-related pathways through modulation of body peptides.

This product is not intended to diagnose, treat, cure, or prevent any disease.

Doctor's Best is a well respected, science‑based brand in the supplement world, known for delivering transparent, research‑backed formulations. This brand has been carefully reviewed by our expert team of doctors, nurses, and nutritionists for alignment with Welzo's standards, and we are confident in Doctor's Best as a reliable partner for this amino acid product. The product itself concentrates on a clearly defined active ingredient—D‑phenylalanine—with a 500 mg per capsule dosage, supported by vegetarian capsule shells and inert additives, reflecting a straightforward, purity‑driven approach that matches our brand expectations. Our team prioritises brands with a transparent, science‑led approach to ingredient selection and dosing, and Doctor's Best meets these criteria through its clear formulation strategy and dosage clarity. This brand's selection is reinforced by our quality certification process, which ensures rigorous review of ingredients and manufacturing practices as part of our vetting.