Relentless Improvement: do you self test the purity of overseas ingredients before production of D-Serine?

When the active arrives we sample it and send it out to a third-party analytical testing laboratory based in the USA. The material is quarantined until test results are received back. **As is required for GMP compliance.**

Is this made in the usa? is it based on porcine aka pig, or shell fish?

The active is not available from USA suppliers. As you are well aware, our high-tech manufacturing was gutted and shipped offshore decades ago. Downstream of the active, all remaining manufacturing and testing is USA. The is no porcine, or shellfish.

Relentless Improvement: do you third party test the purity of overseas ingredients before production of third D-Serine?

As required under GMP, yes. OF COURSE. We have conducted full third-party testing since we began business 17 years ago, before it was required by law. I'll also point out, 99% of actives used by ALL supplement companies come from "overseas" as USA manufacturing was gutted decades ago.

For anyone who's tried both L-Serine & D-Serine, did D-Serine really achieve better results?

Because D-Serine has a poor absorption rate orally one must take a lot. I gave to my wife for three months when recovering. I don't know how well it worked but I would do again.

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Relentless Improvement D-セリン

Product ID: 735149005

Details

Brand
Relentless
Dosage Form
カプセル
Flavor
アンフレーバー
Item Form
カプセル
Item Weight
0.11 Kilograms
Item dimensions L x W x H
6.4 x 5.1 x cm

🌱90 vegecaps, clean & stearate-free

💊700mg pure D-Serine per capsule

🧠Supports cognitive & mood health

€ 154.98

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Description

🧠 Elevate your mind, own your day with D-Serine!

PURE COGNITIVE BOOST - Each capsule delivers a potent 700mg of D-Serine, fueling your brain’s natural performance.
CLEAN GREEN FORMULA - 90 vegetable-based capsules free from magnesium stearate for a pure, allergen-conscious supplement.
TAILORED DOSAGE FLEXIBILITY - Recommended 3-4 capsules daily, with benefits increasing up to 6-8 capsules based on your needs.
MOOD MENTAL CLARITY SUPPORT - Scientifically designed to enhance emotional balance and cognitive function for the busy professional.
TRUSTED QUALITY BY RELENTLESS IMPROVEMENT - Backed by a 4.2-star rating and crafted with premium ingredients for your wellness journey.

D-Serine by Relentless Improvement is a high-potency, clean-label amino acid supplement designed to support healthy cognition and mood. Each capsule contains 700mg of pure D-Serine in a vegetable capsule free from magnesium stearate, offering flexible dosing from 3 to 8 capsules daily. Perfect for professionals seeking mental clarity and emotional balance, this supplement combines science-backed ingredients with trusted quality.

Specifications

ASIN	B09TWCN545
ASIN	B09TWCN545
Brand Name	Relentless Improvement
Customer Reviews	4.2 4.2 out of 5 stars (23)
Dosage Form	カプセル
Flavor	アンフレーバー
Item Dimensions	6.4 x 5.1 x 5.1 cm
Item Form	カプセル
Item Weight	0.11 Kilograms
Item model number	DSERINE_FBM
Manufacturer	Relentless Improvement
Manufacturer	Relentless Improvement
Manufacturer Part Number	DSERINE_FBM
Model Number	DSERINE_FBM
Number of Items	1
Product Dimensions	6.35 x 5.08 x 5.08 cm; 111 g
Specific Uses For Product	感情的なサポート
UPC	854463005412

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Yes, all products are sourced directly from authorized retailers in the US, UK, UAE and India. We maintain strict quality control processes and verify each product before shipping. All items come with applicable manufacturer warranties and are covered by our standard return policy.

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How is product pricing calculated?+

Our prices include the product cost, international shipping, import duties, customs clearance, and local delivery charges. We handle all customs and import procedures, ensuring there are no hidden fees upon delivery. PRO members receive additional benefits including free shipping.

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TrustScore 4.5 | 7,300+ reviews

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Excellent communication throughout the order process. Product is perfect.

2 weeks ago

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The MOLLE sheath is of exceptional quality. Very happy with my purchase.

2 weeks ago

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€ 154.98

Duties & taxes included

In stock

Sold byAmazon SpainDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

Buyer Protection · Full refund if your order doesn't arrive as described.

Desertcart purchases this item on your behalf and handles shipping, customs, and support to Spain.

Secure transaction

ProDesertcart PRO

Fast, free shipping, member pricing & priority support.

Join PRO →

Trustpilot

TrustScore 4.5 | 7,300+ reviews

Abdullah B.

Great price for an authentic product. Fast international shipping too!

3 weeks ago

Zainab N.

Fantastic and great service. Shipping was faster than expected.

1 week ago

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