What Is Cycloastragenol? A Complete Guide to Purity, Science and Quality — From a Professional Manufacturer

By Chengdu King-tiger Pharm-chem. Tech. Co., Ltd. — a professional manufacturer of Astragalus extracts (astragaloside IV and cycloastragenol) since 2007. Last updated: September 2026.

Cycloastragenol is one of the most talked-about natural compounds in the longevity and healthy-aging industry. Search for it online and you will find hundreds of suppliers — but very few of them actually manufacture it, and fewer still can prove what is really inside the drum. In this guide, we explain what cycloastragenol is, what the science says, and — most importantly — the hidden quality problem that separates real cycloastragenol 98% from material that only looks pure on a certificate.

1. What Is Cycloastragenol?

Cycloastragenol (CAG) is a tetracyclic triterpenoid saponin aglycone obtained from astragaloside IV, the flagship active constituent of Astragalus membranaceus (Fisch.) Bge. — the medicinal herb known in China as Huangqi (黄芪) and revered in Traditional Chinese Medicine for more than 2,000 years as a supreme qi-tonifying herb.

When the sugar units are removed from astragaloside IV, the remaining aglycone is cycloastragenol — a smaller, more lipophilic molecule with a characteristic 9,19-cyclolanostane skeleton and four hydroxyl groups.

Basic Chemical Profile

2. From Astragalus to Cycloastragenol: The Relationship with Astragaloside IV

Many buyers confuse the three members of the Astragalus saponin family. The chain is simple:

Astragalus root → Astragaloside IV (glycoside) → Cycloastragenol (aglycone)

• Astragaloside IV is the natural glycoside present in the plant. It is the best-studied Astragalus marker compound and the "starting point" of the family.
• Cycloastragenol is produced by removing the sugar groups from astragaloside IV. The smaller molecule is more lipophilic and shows better membrane permeability, which is why it has attracted intense research interest in the fields of telomere biology and immune senescence.

Because cycloastragenol exists only in trace amounts in the raw herb, commercial CAG must be manufactured from extracted astragaloside IV through controlled conversion and purification. This is precisely where quality problems begin — as we explain in Section 5.

How Cycloastragenol Is Manufactured

Producing genuine high-purity cycloastragenol at commercial scale requires real process control, not just a recipe. The five core steps are:

1. Raw material selection — dried Astragalus root from the Gansu or Inner Mongolia growing regions, tested on arrival.
2. Extraction — astragalosides (including astragaloside IV) are pulled from the root with food-grade solvent systems.
3. Hydrolysis — King-tiger's proprietary process converts astragaloside IV into the aglycone cycloastragenol under mild, precisely controlled conditions. This is the critical step: poorly controlled hydrolysis generates the by-product astragenol discussed in Section 5.
4. Purification — Purified to 98% by King-tiger's proprietary green process technology.
5. Drying and finishing — spray drying or vacuum drying under controlled conditions, then packaging.

At Chengdu King-tiger, all products are made using only food-grade ethanol and water as processing solvents, keeping the entire process green, environmentally friendly, and safe.

3. The Science: Why the World Is Interested in Cycloastragenol

3.1 Telomerase activation

Cycloastragenol became famous as one of the first small molecules reported to activate telomerase, the enzyme that lengthens telomeres — the protective caps at the ends of chromosomes that shorten with each cell division. A study in The Journal of Immunology (Fauce et al., 2008) reported that cycloastragenol (research name TAT2) modestly enhanced telomerase activity, proliferative capacity and antiviral function in CD8+ T lymphocytes from HIV-infected human donors — and that these effects disappeared when a specific telomerase inhibitor was applied, pointing to telomerase as the relevant target. A widely cited study by Harley et al., published in Rejuvenation Research (2011), reported that low-nanomolar TA-65, a cycloastragenol-based formulation, moderately activated telomerase in cultured human keratinocytes, fibroblasts and immune cells; subsequent research has explored its effects on T-cell aging, skin biology, and oxidative stress. Commercially, cycloastragenol is best known as the active principle behind the early telomerase-activating supplement TA-65, which is largely credited with bringing the molecule to the attention of the longevity industry.

In preclinical studies, CAG has been reported to:

• Extend telomeres in certain human cell types and delay replicative senescence;
• Support the proliferative capacity of CD4+ and CD8+ T-lymphocytes, which normally lose telomerase activity with age;
• Upregulate TERT gene expression under oxidative stress conditions.

3.2 Immune function and healthy aging

Because telomere shortening in immune cells is a hallmark of immunosenescence, CAG has been studied for supporting immune function in aging populations. Published preclinical research also explores its anti-inflammatory, cardioprotective, and neuroprotective potential, including effects on NLRP3 inflammasome pathways and CREB signaling. More recently, a 2023 study in the International Journal of Molecular Sciences reported that cycloastragenol can act as a senolytic — selectively inducing apoptosis in senescent cells and suppressing their inflammatory secretions — in aged mouse models, making CAG one of the few natural compounds studied for both telomerase activation and senescent-cell clearance.

3.3 A Second Mechanism: Cathepsin B and Antitumor Immunity (2022)

Beyond telomeres, the most significant recent finding came in October 2022, when researchers from Nanjing University of Chinese Medicine and Nanjing University published a study in the Journal for ImmunoTherapy of Cancer (Deng et al., 2022; DOI: 10.1136/jitc-2022-004874) identifying a direct molecular target of cycloastragenol: cathepsin B (CTSB), with binding at residues A77 and G198.

Working in mouse colorectal cancer models (MC38 and CT26) and using single-cell multi-omics sequencing, the team showed that by binding CTSB, cycloastragenol inhibits the lysosomal degradation of MHC-I (major histocompatibility complex I). More MHC-I stays on the tumor-cell surface, so more tumor antigen is displayed where CD8+ T cells can recognize it. In combination with anti-PD-1 antibody therapy, CAG enhanced the tumor-killing capacity of CD8+ T cells — in transplanted-tumor mice and in colorectal cancer organoids co-cultured with human peripheral blood T cells.

Why this matters for ingredient buyers: the study gives a mechanistic, target-level explanation for Huangqi's traditional "qi-supporting" (扶正) role in TCM oncology formulas, and it has made cycloastragenol a reference compound in immuno-oncology preclinical research. It also means demand for high-purity, fully characterized CAG is no longer limited to the supplement industry. All findings to date are preclinical (cell and animal models) — no anticancer claims for CAG ingredients are implied or permitted.

Note: Most evidence comes from in-vitro and animal studies. Cycloastragenol is sold as an ingredient for dietary supplements and cosmetics, and is not intended to diagnose, treat, cure or prevent any disease. Responsible marketing of CAG-based finished products should follow the regulations of the target market (FDA structure/function claims in the US, EFSA rules in the EU, etc.).

4. Applications of Cycloastragenol

• Longevity & healthy-aging supplements — often formulated at low-dose daily intake, frequently in NAD+ or "telomere support" stacks;
• Immune-support formulations — alone or combined with Astragalus polysaccharides and other Astragalus actives for whole-herb-synergy positioning;
• High-end skin care — studied for dermal fibroblast senescence and used in premium anti-aging serums;
• Research use — high-purity CAG (≥98%, HPLC ≥99%) is directly usable as a reference substance, and is increasingly in demand for immuno-oncology and senescence research following the 2022 cathepsin B study;
• Other new-drug research — beyond the fields above, cycloastragenol also serves as a lead compound in other drug discovery and development programs.

5. The Hidden Problem: Astragenol, the By-Product Nobody Talks About

One quality issue deserves every buyer's attention. A poorly controlled production process generates an open-ring by-product called astragenol, whose structure is so similar to cycloastragenol that ordinary HPLC methods cannot separate the two compounds. The consequence: in our own comparative testing, a commercial sample sold as "cycloastragenol 98%" with a COA value of 98.74% contained only 60.45% true cycloastragenol — the difference was largely astragenol.

After seven years of process research, Chengdu King-tiger's production technology avoids generating astragenol in the first place, and our validated detection method fully separates the two compounds. Our cycloastragenol 98% shows no detectable astragenol and a true HPLC purity of 99.33% — confirmed by ¹H-NMR and by Intertek (USA), an authorized independent third-party laboratory. Full chromatograms and test reports are published on our cycloastragenol product page.

For the complete technical analysis — how astragenol forms during production, why it can fake a certificate of analysis, and a 10-minute due-diligence protocol to detect it — read our dedicated article: Astragenol vs Cycloastragenol: The Impurity That Can Fake Your COA.

6. How to Verify Cycloastragenol Quality Before You Buy

Whether you buy from us or from another manufacturer, we recommend a simple due-diligence checklist:

1. Ask which detection method is used. Cycloastragenol has weak UV absorption; it must be quantified by HPLC-RID or HPLC-ELSD — the HPLC detector cannot be a UV detector.
2. Ask whether the method separates astragenol. Request the actual chromatogram, not just a number. If the method cannot resolve the astragenol peak, the assay is unreliable.
3. Ask for third-party test reports from internationally recognized institutions, covering three or more consecutive years, to confirm that the material is genuinely of 98%+ grade.
4. Ask about regulatory compliance. For example, our Astragalus extract products fully meet EU requirements on PAHs — see our PAHs compliance statement.
5. Buy from a professional manufacturer that controls the full chain from raw material (Gansu and Inner Mongolia growing regions) to purification.

7. King-Tiger Cycloastragenol: Specifications and Supply

• Purity range: 1.00% – 99.00% (1%, 5%, 10%, 50%, 90%, 98% standard grades);
• 98% grade: pure white powder, HPLC purity above 99%, directly usable as a reference substance;
• Low-purity grades: 100% natural Astragalus extract — the non-CAG fraction consists of natural Astragalus constituents (polysaccharides, saponins, flavonoids), suitable for whole-herb formulations;
• Stock: all specifications available in large quantity from stock at any time;
• Documentation: COA, chromatograms, and third-party test report provided with every batch.

Buyers formulating beverages, liquid tinctures, or other water-based delivery systems can also request a water-soluble cycloastragenol grade (5%–10%), developed for finished products where a powder-in-water solution is required.

8. Frequently Asked Questions

9. About Chengdu King-tiger

Founded in 2007, Chengdu King-tiger Pharm-chem. Tech. Co., Ltd. is one of the few professional manufacturers in China specializing in natural high-purity compounds from traditional Chinese medicine and medicinal herbs, including the complete Astragalus extract series — cycloastragenol, astragaloside IV (0.3%–99%), astragalus polysaccharides, and Calycosin 7-O-beta-D-glucoside.

Founded by Dr. Chen, who has devoted nearly two decades to the research, separation and production of high-purity Astragalus extracts — cycloastragenol, astragaloside IV, astragalus polysaccharides, and Calycosin 7-O-beta-D-glucoside.

Our core business is the research, development, separation and purification of biologically active natural compounds. When you source cycloastragenol from King-tiger, you buy directly from the company that develops the process, runs the production line, and stands behind every chromatogram.

Chengdu King-tiger is among the drafting units of T/CCCMHPIE 1.54—2021, the group standard for Astragalus extracts for export, published by the China Chamber of Commerce for Import and Export of Medicines and Health Products (CCCMHPIE).

Ready to source verified, astragenol-free and safety-assured cycloastragenol? Visit our cycloastragenol.html for full specifications, chromatograms and test reports, or contact us for a quotation and samples.