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.

Fully operational. Shipping worldwide, on schedule.Duty & taxes paid at delivery

Help Track order

Account Cart

Fully operational. Shipping worldwide, on schedule.Duty & taxes paid at delivery

Help Track order

Account Cart

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

COP 616391

Duties & taxes included

In stock

Sold byAmazon ColombiaDelivered 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 Colombia.

Secure transaction

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

Common Questions

Are the products genuine and authentic?+

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.

How long does delivery take and is it reliable?+

Delivery times vary by destination country, typically ranging from 3-9 business days. Each order is fully trackable through our system. We handle all customs clearance and use reliable courier partners for last-mile delivery. You'll receive regular updates about your order status via email and our app.

What is Desertcart? Is it safe to order from?+

Desertcart is an international e-commerce platform operating since 2014. We securely process thousands of orders globally each day. Every product goes through our quality verification process before delivery, and we provide end-to-end order tracking, 24/7 customer support, and a comprehensive returns policy to ensure a safe shopping experience.

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.

Trustpilot

TrustScore 4.5 | 7,300+ reviews

Fatima A.

Best international shipping I've ever tried. Worth every penny!

3 days ago

Rajesh P.

Customer service was outstanding when I had questions about the product.

2 days ago

View all Trustpilot reviews

Shop Global, Save with Desertcart

Value for Money

Competitive prices on a vast range of products

Shop Globally

Serving millions of shoppers across more than 100 countries

Enhanced Protection

Trusted payment options loved by worldwide shoppers

Customer Assurance

Trusted payment options loved by worldwide shoppers.

Desertcart App

Shop on the go, anytime, anywhere.

COP 616391

Duties & taxes included

In stock

Sold byAmazon ColombiaDelivered 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 Colombia.

Secure transaction

Trustpilot

TrustScore 4.5 | 7,300+ reviews

Farhan Q.

The delivery time was excellent, and the packaging was secure.

2 months ago

Anjali K.

The product quality is outstanding. Exactly what I needed for my work.

1 month ago

View all Trustpilot reviews