Flex (CD)™

TCM herbal formula for cold-type arthritis, joint degeneration, and fibromyalgia — analgesic; anti-inflammatory; antirheumatic; chondroprotective; osteogenic; expels wind, cold, and damp; warms channels and collaterals; tonifies Kidney yin and yang; invigorates blood circulation

⚠️ Do not use if the patient presents with heat signs such as redness, burning, or inflammation of the joints that worsens with heat — use Flex (Heat) instead. Contraindicated during pregnancy and nursing. Contains Dang Gui Wei (Extremitas Radix Angelicae Sinensis), which invigorates blood circulation — patients on anticoagulant or antiplatelet therapies such as Coumadin (warfarin) should use with caution or not at all due to higher risk of bleeding and bruising. Patients who wear a pacemaker, take antiarrhythmic drugs or cardiac glycosides such as Lanoxin (digoxin), or have pre-existing cardiovascular problems should not take this formula — Zhi Cao Wu and Zhi Chuan Wu may affect heart rhythm and potentiate contractile strength. Side effects may include nausea, vomiting, stomach discomfort, and irritability — discontinue if these occur.

CLINICAL APPLICATIONS

* Chronic cold-type arthritis or arthralgia that worsens with cold and damp weather

* Chronic low back pain and sciatica with underlying deficiencies

* Degenerative disorders with weakness of the lower back and knees with reduced mobility

* General aches and pains characterized by cold manifestations

* Fibromyalgia characterized by cold or numbness

Background: Musculoskeletal and connective tissue disorders are major causes of pain and physical disability. Causes vary greatly — simple causes include trauma and external injuries (pulled muscles, strained ligaments, dislocated joints, bone fractures); complicated causes include infection, autoimmune disorders, crystal-induced inflammation, and non-inflammatory tissue degeneration. Optimal treatment must address the symptom (pain and inflammation) and the underlying causes. After the disorder is stabilized, physical therapy and exercise are important to maintain flexibility and strengthen surrounding muscles.

Key herb-level clinical data:

— Yan Hu Suo (Rhizoma Corydalis / Corydalis): one of the strongest analgesic herbs — analgesic potency comparable to morphine; satisfactory anesthetic effect in 98 of 105 patients (93.4%) undergoing surgery; analgesic effect significantly potentiated with concurrent electro-acupuncture; safer than morphine — fewer side effects, less risk of tolerance, no physical dependence even with long-term use

— Zhi Chuan Wu (Radix Aconiti Praeparata / Prepared Aconite): restores Kidney yang; dispels cold; warms channels and collaterals; analgesic and anti-inflammatory — aconitine acts on the central nervous system; anti-inflammatory effect stronger than aspirin; clinically: arthritis, shoulder inflammation, heel spurs; low back pain in 225 patients — 87.4% effective (10–15 days daily use); frozen shoulder in 35 patients — 22 significant improvement, 8 moderate, 4 slight, 1 no effect

— Zhi Cao Wu (Radix Aconiti Kusnezoffii Praeparata / Prepared Kusnezoff Aconite): restores Kidney yang; dispels cold; warms channels and collaterals; analgesic and anti-inflammatory — aconitine CNS action; anti-inflammatory stronger than aspirin; clinically: topical application for periarthritis of the shoulders and sciatica

— Du Huo (Radix Angelicae Pubescentis / Angelica Pubescens): antirheumatic, anti-inflammatory, and analgesic — expels wind, dampness, and cold from the lower back; removes painful obstruction

— Qin Jiao (Radix Gentianae Macrophyllae / Gentiana Macrophylla): antirheumatic, anti-inflammatory, and analgesic — expels wind, dampness, and cold; removes painful obstruction

— Fang Feng (Radix Saposhnikoviae / Saposhnikovia / Siler): antirheumatic, anti-inflammatory, and analgesic — expels wind, dampness, and cold; inhibits nitric oxide synthase (iNOS) — suppresses nitrite production

— Du Zhong (Cortex Eucommiae / Eucommia Bark): replenishes Liver and Kidney — strengthens bones, sinews, and muscles of the lower back and knees; osteogenic and antiosteoporotic — promotes osteoblast proliferation and differentiation, increases tissue regeneration of damaged bones; anti-inflammatory — stimulates endocrine system and adrenal cortex steroid secretion

— Di Huang (Radix Rehmanniae / Rehmannia): replenishes Liver and Kidney — strengthens bones, sinews, and muscles; anti-inflammatory — increases plasma levels of adrenocortical hormone even in presence of dexamethasone; clinically: rheumatoid arthritis (12 patients in herbal formula)

— Sang Ji Sheng (Herba Taxilli / Taxillus / Loranthus): replenishes Liver and Kidney — strengthens bones, sinews, and muscles; antirheumatic and anti-inflammatory — especially effective for general body aches and pains

— Chuan Niu Xi (Radix Cyathulae / Cyathula): replenishes Liver and Kidney; chondroprotective — inhibits MMP-13 (key enzyme for cartilage collagen matrix degradation under arthritic conditions)

— Wei Ling Xian (Radix et Rhizoma Clematidis / Clematis): increases qi and blood circulation; relaxes muscles and tendons; antirheumatic and antiarthritic — inhibits pro-inflammatory compounds and prevents rheumatoid arthritis; chondroprotective — inhibits MMP-3, MMP-13, and COX-2; prevents extracellular matrix degradation and cartilage erosion in osteoarthritis

— Bai Shao (Radix Paeoniae Alba / White Peony): analgesic, antispasmodic, and anti-inflammatory

— Dang Gui Wei (Extremitas Radix Angelicae Sinensis / Angelica Sinensis Tail): increases qi and blood circulation to the extremities; relaxes muscles and tendons; analgesic and anti-inflammatory — inhibits NO and PGE2; anti-inflammatory 1.1× stronger than aspirin; analgesic 1.7× stronger than aspirin; osteogenic — stimulates type I collagen synthesis and proliferation of osteoprecursor cells

— Chuan Xiong (Rhizoma Chuanxiong / Ligusticum Chuanxiong): increases qi and blood circulation to the extremities; relaxes muscles and tendons; anti-inflammatory — inhibits TNF-α and NF-κB (phthalide lactones)

— Qian Nian Jian (Rhizoma Homalomenae / Homalomena): increases qi and blood circulation to the extremities; relaxes muscles and tendons

— Wu Jia Pi (Cortex Acanthopanacis / Acanthopanax / Eleuthero Bark): increases qi and blood circulation to the extremities; relaxes muscles and tendons; tonifies qi; addresses underlying deficiencies

— Ji Xue Teng (Caulis Spatholobi / Spatholobus): increases qi and blood circulation to the extremities; relaxes muscles and tendons; anti-inflammatory — inhibits COX, phospholipase, and lipoxygenase

— Ren Shen (Radix et Rhizoma Ginseng / Ginseng): tonifies qi; addresses underlying deficiencies

WESTERN THERAPEUTIC ACTIONS

* Analgesic — Yan Hu Suo (morphine-comparable, 93.4% surgical anesthesia); Zhi Chuan Wu + Zhi Cao Wu (aconitine CNS, stronger than aspirin, 87.4% low back pain); Dang Gui Wei (1.7× aspirin)

* Anti-inflammatory — Fang Feng (iNOS↓, nitrite↓); Dang Gui Wei (NO↓, PGE2↓, 1.1× aspirin); Chuan Xiong (TNF-α↓, NF-κB↓); Du Zhong (adrenal cortex steroids↑); Di Huang (adrenocortical hormone↑); Ji Xue Teng (COX↓, phospholipase↓, lipoxygenase↓); Zhi Chuan Wu + Zhi Cao Wu (aconitine, stronger than aspirin)

* Antirheumatic / antiarthritic — Du Huo + Sang Ji Sheng (general body aches and pains); Wei Ling Xian (rheumatoid arthritis prevention, pro-inflammatory compounds↓); Qin Jiao (wind-damp-cold obstruction)

* Chondroprotective — Chuan Niu Xi (MMP-13↓); Wei Ling Xian (MMP-3↓, MMP-13↓, COX-2↓, extracellular matrix protection)

* Osteogenic — Du Zhong (osteoblast proliferation↑, bone tissue regeneration↑); Dang Gui Wei (type I collagen↑, osteoprecursor cell proliferation↑)

CHINESE THERAPEUTIC ACTIONS

* Expels wind, cold, and damp; removes painful obstruction (Du Huo, Qin Jiao, Fang Feng)

* Warms channels and collaterals; restores Kidney yang (Zhi Chuan Wu, Zhi Cao Wu)

* Tonifies Kidney yin and yang; replenishes Liver and Kidney (Du Zhong, Di Huang, Chuan Niu Xi, Sang Ji Sheng)

* Invigorates blood circulation; relaxes muscles and tendons (Dang Gui Wei, Chuan Xiong, Wei Ling Xian, Ji Xue Teng, Wu Jia Pi, Qian Nian Jian)

* Analgesic; antispasmodic (Yan Hu Suo, Bai Shao)

* Tonifies qi; addresses underlying deficiencies (Ren Shen, Wu Jia Pi)

DOSAGE

Standard: 3–4 capsules three times daily with a glass of warm water. Severe pain: up to 6 capsules every 6 hours as needed.

Clinical notes: Avoid exposure to rain, wind, and cold weather whenever possible. Always wear warm clothes and cover the body and joints. Never use ice packs for joint pain due to coldness — use heat pads instead.

Supplementary formulas: Neck and shoulder pain — combine with Neck & Shoulder (AC) or Neck & Shoulder (CR). Lower back pain — add Back Support (AC) or Back Support (CR). Herniated disk with swelling and inflammation — add Back Support (HD). Arm pain — add Arm Support. Knee pain — add Knee & Ankle (AC) or Knee & Ankle (CR). Spasms and cramps — combine with Flex (SC). Bone fractures, injuries, and bruises — combine with Flex (TMX). Post-stroke numbness and atrophy — use Neuro Plus. Bone spurs — add Flex (SPR). Osteoporosis prevention and treatment — add Osteo 8. Muscle, ligament, and tendon degeneration — add Flex (MLT). Enhanced analgesia — add Herbal ANG. Arthritic pain with inflammation, swelling, redness — use Flex (Heat) instead. Severe Kidney yin deficiency — add Kidney Tonic (Yin). Severe Kidney yang deficiency — add Kidney Tonic (Yang).

Nutrition: Sulfur helps calcium absorption — essential for repair and rebuilding of bones, tendons, cartilage, and connective tissues; eat foods high in sulfur such as asparagus, eggs, fresh garlic, and onions. Histidine (an amino acid) removes excess copper and iron found in arthritic patients — eat foods high in histidine such as rice, wheat, and rye. Fresh pineapple contains bromelain — excellent for reducing inflammation. For gout: increase cherries and strawberries (neutralize uric acid) and water intake (flushes uric acid). Avoid foods containing purines or uric acid: meat, anchovies, herring, meat gravies and broths, mushrooms, mussels, sardines, sweetbreads, fried foods, and alcohol. Avoid cold beverages, uncooked foods, ice cream, caffeine, sugar, tomatoes, milk, dairy products, and red meat. Decrease sour foods, drinks, and citrus — their constricting nature may contribute to further stagnation in the channels and collaterals. Fish oil may help alleviate pain associated with rheumatoid arthritis — can be taken alongside the herbs.

Tao of Nutrition (Dr. Maoshing Ni and Cathy McNease): Recommended foods: garlic, green onions, pepper, black beans, sesame seeds, chicken, lamb, mustard greens, ginger, and a small amount of rice wine (if no hypertension). Rub garlic or ginger on the painful areas — or burn moxa on a slice of ginger over the painful areas. Drink scallion tea and rub it on the painful areas. Rub rice wine on the painful areas and drink one small glass in the evening. Drink grape vine tea added to red wine. Make tea from parsnip, cinnamon, black pepper, and dried ginger. Avoid cold foods, raw foods, and cold weather elements.

Lifestyle: Weight loss is strongly recommended for overweight patients — lessens pressure on joints and helps relieve pain. Exercise is recommended; however, avoid sports such as swimming or skiing that expose affected joints to cold and dampness.

CASE STUDIES

— 57-year-old female (F.L.): Fibromyalgia; tendency to feel cold all the time; Spleen qi deficiency with damp, Kidney yin and yang deficiencies. Flex (CD). Result: good results; continued formula for 2 years to maintain results; no longer felt cold; less pain with nutritional guidance; very pleased.

— 89-year-old male (P.M.): Chronic back pain and sciatica for 4 months — triggered by sitting in cold weather at a football game and at wife's funeral; bilateral leg, knee, and buttock pain (right worse than left); pitting edema both ankles; BP 130/80, HR 80; trigger points at left QL, glute, L3, L4; bi zheng due to cold, Kidney qi deficiency, qi and blood stagnation in GB channel. Flex (CD) 4 capsules 2x/day + 3 acupuncture visits. Result: 90% better; planned European walking vacation.

— 48-year-old female (C.M.): Joint pain (hands, feet, knees) worsening in cold and rainy weather; family history of arthritis and osteoporosis; tendonitis both forearms; decreased ROM; calcification of finger joints; rheumatoid arthritis (Western); cold and damp obstruction (TCM). Osteo 8 + Flex (CD) 4 capsules each 2x/day. Result within 1 day: symptoms began improving; after 1 week: joints and tendons not stiff, almost pain-free; symptoms improved even during winter; symptoms returned when herbs stopped.

— 73-year-old female daycare worker: Constant pain in low back, right hip, and right knee from osteoarthritis — aggravated by activity and prolonged sitting; sharp pain on walking; fatigue, dizziness, intermittent high BP; red tongue with scanty coat; irregular hesitant thready pulse at Liver and Kidney positions; choppy irregular weak pulse at Spleen position; Kidney and Liver yin deficiencies, qi and blood stagnation, damp-cold bi zheng. Flex (CD) 3 spoonfuls 2x/day + acupuncture. Result: ~30% reduction in joint pain.

— 63-year-old female homemaker: Sciatica-like pain in lumbar and left sacral region — worse in evening, cold to the touch; left ankle swelling (cold on palpation, chronic pain ~1 year); cold symptoms relieved by warmth; disc herniation L3–L4; thin red tongue with thick coat at base; tight deep pulse; Liver and Kidney yin deficiencies, Kidney yang deficiency, wind-damp bi zheng. Flex (CD) 3 capsules 3x/day. Result: significant decrease in pain during initial treatment; minor indigestion resolved quickly; after 3 bottles: pain manageable enough to return to exercise.

Related Reading

Also see: Flex (Heat) – for hot-type arthritis with redness and inflammation | Back Support (CR) – for chronic low back pain | Back Support (AC) – for acute back pain | Back Support (HD) – for herniated disc | Neck & Shoulder (CR) – for chronic neck and shoulder pain | Knee & Ankle (CR) – for chronic knee pain | Flex (SC) – for spasms and cramps | Flex (MLT) – for muscle, ligament, and tendon degeneration | Flex (SPR) – for bone spurs | Osteo 8 – for osteoporosis | Kidney Tonic (Yang) – for Kidney yang deficiency | Kidney Tonic (Yin) – for Kidney yin deficiency | Herbal ANG – to enhance analgesia | Pain Relief & Musculoskeletal Support Collection.