Diabetic peripheral neuropathy is a symmetrical nerve injury that usually starts in the toes and creeps upward.

Doctors call it a “glove and sock” distribution.

Patients call it:

  • Tingling
  • Numbness
  • Burning pain
  • Knife-like stabbing
  • Electric shocks

Roughly 1 in 3 patients with DPN develop significant pain.

And it’s not just discomfort. Loss of sensation in the feet is the #1 driver of:

  • Foot ulcers
  • Infections
  • Amputations

In one large Chinese screening program, about 53% of people with diabetes had DPN.

That’s massive.

Why Does DPN Happen?

Short answer: high blood sugar slowly poisons nerves.

Long answer:

Chronic hyperglycemia triggers:

  • Oxidative stress
  • Inflammation
  • Microvascular damage
  • Advanced glycation end products (AGEs)
  • Nerve fiber loss

There’s reduced blood flow to nerves.
There’s direct metabolic injury.
There’s inflammatory damage.

It’s a multi-hit problem.

Which is why treating it is hard.

Current Treatment = Mostly Damage Control

Standard care focuses on:

  • Better glucose control
  • Blood pressure management
  • Lipid control
  • Pain medications
  • Improving microcirculation

But let’s be honest:
Most therapies manage symptoms.
They don’t fully reverse nerve injury.

That’s where traditional Chinese medicine (TCM) enters the chat.

The Herbal Formula in Question: Tongmai Jiangtang Capsules

The formula is called:

Tongmai Jiangtang Capsules (TJCs)

It’s a multi-herb blend designed under TCM theory to:

  • “Nourish Yin”
  • “Invigorate Qi”
  • Improve circulation
  • Reduce “blood stasis”

Translation into modern physiology?

Improve blood flow, reduce inflammation, regulate glucose, and support nerve health.

The ingredients include herbs like:

  • Astragalus
  • Salvia miltiorrhiza
  • Coptis
  • Pueraria
  • Dioscorea
  • Scrophularia

Each one has proposed metabolic or anti-inflammatory properties.

What Did This Study Actually Do?

Instead of running a new clinical trial, researchers did something else:

They conducted a systematic review and meta-analysis of existing randomized controlled trials.

They compared:

Conventional therapy (CT) alone
vs
Conventional therapy + Tongmai Jiangtang Capsules

The key outcomes?

Objective nerve function measurements:

  • Motor nerve conduction velocity (MNCV)
  • Sensory nerve conduction velocity (SNCV)

Basically: how fast electrical signals travel through damaged nerves.

Faster conduction = healthier nerves.

The Headline Result

When TJCs were added to standard therapy:

Nerve conduction speeds improved.

Specifically:

  • Median nerve conduction improved
  • Peroneal nerve conduction improved

That suggests improved nerve function.

But…

There’s a catch.

Actually, several.

The Big Asterisk: Study Quality Wasn’t Great

The meta-analysis found:

  • High heterogeneity (studies were very different from each other)
  • Poor reporting of randomization methods
  • Little mention of blinding
  • Different Western medications used across trials
  • No consistent protocol

In short:

The signal looks promising.
But the research quality wasn’t strong.

Which means we can’t make bold clinical claims yet.

Why Might This Formula Work? (Mechanistically)

Here’s where it gets interesting.

Modern lab studies show TJCs may:

1) Reduce Inflammation

They lower inflammatory markers like:

  • TNF-α
  • IL-6

These are major players in diabetic nerve damage.

They also appear to protect Schwann cells — the support cells that wrap peripheral nerves.

In diabetes, those cells undergo apoptosis (cell death).
TJCs seem to reduce that.

2) Improve Microcirculation

Some ingredients:

  • Reduce platelet aggregation
  • Lower blood viscosity
  • Dilate blood vessels

Better blood flow = better oxygen and nutrient delivery to nerves.

3) Improve Insulin Resistance

Compounds like β-sitosterol (found in Scrophularia) have been shown in animal models to:

  • Improve insulin sensitivity
  • Modulate IRS-1/Akt pathways
  • Activate AMPK and GLUT-4

That’s real metabolic signaling territory.

4) Multi-Target Effect

Unlike single-molecule drugs, this formula hits:

  • Inflammation
  • Lipid metabolism
  • Insulin resistance
  • Microvascular function
  • Possibly nerve cell survival

That multi-pathway approach may be useful in a disease as complex as DPN.

What About Safety?

Five of eight included studies reported safety data.

No major adverse drug reactions were reported.

But:

The trials were small.
Long-term safety monitoring was limited.
And reporting standards weren’t ideal.

So we can’t call it definitively “safe” yet — just “no red flags so far.”

The Limitations You Should Know

  • All studies were conducted in China.
  • Patient race and broader demographics weren’t well defined.
  • Trial methodology was generally low quality.
  • Western therapies varied widely.
  • Few studies followed strict CONSORT or SPIRIT trial standards.

In evidence-based medicine terms:

This is encouraging, but not definitive.

So Should Clinicians Use It?

The authors suggest:

TJCs may be a useful adjunct to conventional therapy.

Not a replacement.

Add-on.

Especially when monitored carefully.

But they also emphasize:

We need larger, multicenter, rigorously designed randomized trials.

With:

  • Standardized outcomes
  • Clear adverse event reporting
  • Proper randomization
  • Long-term follow-up

The Recap

Diabetic peripheral neuropathy is a slow-burning disaster for millions of people.

Painful.
Costly.
Life-altering.

This herbal formula shows signals of benefit:

Better nerve conduction.
Reduced inflammation.
Improved microcirculation.

But the evidence isn’t ironclad yet.

It’s a “promising but needs better trials” story.

And in complex chronic diseases like DPN, multi-target approaches might be part of the future — especially when combined with optimized glucose control and vascular protection.

The next step?

High-quality global trials.

Because if we can actually slow nerve damage — not just numb the pain — that would be a real breakthrough.

Sun LX, Li YY, Xie YM. Efficacy and safety of Tongmai Jiangtang capsule combined with conventional therapy in the treatment of diabetic peripheral neuropathy: a systematic review and meta-analysis. Front Neurol. 2023 Apr 26;14:1100327. doi: 10.3389/fneur.2023.1100327. PMID: 37181570; PMCID: PMC10171201.